The other aspect of this subject that I am interested in, is the idea of a virtual focal plane. With an array of cameras (or if you have time instead of budget,

The other aspect of this subject that I am interested in, is the idea of a virtual focal plane. With an array of cameras (or if you have time instead of budget, one camera moved about), you can align the images, and select for a specified focal plane, which can be in almost any angle relative to the camera. Lytro made a camera with a series of microlenses inside that captured a lightfield. As above, this allows focus shifting AFTER the photo was taken. The camera itself had no focusing mechanism, it was fixed... all the focus was in postprocessing. You never had to worry about a blurry shot. Once you get into this experimenting with cameras in different locations, you start to consider Photogrammetry, the measurement of locations by photograph. With a sufficient knowledge of the lens used and a rough idea of location, of each picture, you could assemble an array of images of an object over time, and measure even small shifts in position. Like, for example, brick walls shifting position as buildings settle, etc.